Method for bending tubes of paper, fiber, and similar material



Sept. 13, 1932. D. B. REPLOGLE METHOD FOR SENDING TUBES OF PAPER, FIBER, AND SIMILAR MATERIAL Filed Feb. 1'7, 1950 Patented Sept. 13, 1932 UNITED STATE. PATN'E cries DANIEL BENSON REPLOGLE, OF BERKELEY, CAL IFORN LA, ASSIGNOR TO THE COMMERCE GUARDIAN TRUST & SAVING-S BANK, OF TOLEDO, OHIO, TRUSTEE METHOD FOR BENDIN G TUBES OF PAPER, FIBER, AND SIMILAR MATERIAL Application filed February 17, 1930. Serial No. 429,187.

The invention relates to a method for bending tubes constructed of hygroscopic material such as vulcanized fiber, hard paper tubes, or tubes composed of other cellulose material.

This application is a continuation in part of my copending application, Serial No. 296,073,

filed July 28, 1928.

In the manufacture of fibrous tubes it is the custom to produce the same by winding upon a mandrel a wet web of fibrous pulp such as cellulose pulp, the wet web of 'pulp being formed by a cylinder mold or other web-torming mechanism, and being conveyed to the winding mandrel by any suitable form of 15 conveying means. As a result of this operation, there is formed upon the mandrel a tube having a wall which is substantially homogeneous. l/Vhen the winding operation is completed, the tube itself is moist and it is 530 then ordinarily subjected to a drying operation by which the moisture is removed.

The present invention relates to an improved method of bending such fibrous tubes after the forming mandrel has been removed.

This may be accomplished before the tube is permitted to dry, or if it is dried, the tube may be moistened so as to condition it for the bending operation, for it is a prerequisite that the tube shall be in a condition to bend, and in a moist condition they bend best. A moist paper or fiber tube is easily collapsible since the walls thereof under these conditions possess little strength or resistance.

One of the problems which presents itself in the bending of such tubes is to prevent the malformation of the tube and to maintain the circularity of the tube in cross section.

According to the present invention, the I problem is solved by filling the tube with l sand or other granular material which will serve to maintain the circularity of the moist flexible fiber walls during the bending operation and until the bent tube is dried.

The invention will be more readily understood by reference to the accompanying drawing, in which:

Figure 1 is a perspective view of a form of tube bending device, particularly designed 5 for bending a plurality of tubes which may I or other granular magether the upper and lower members of the apparatus;

Figure 3 is a. view similar to Fig. 2, but taken near one end of the apparatus and showing in elevation the cooperating means for insuring proper registry of the complementary portions of the bending forms; and

Figure 1 is a central longitudinal sectional view through one of the tube-forming mem bers of the apparatus, a bent tube, filled with sand, being shown in section.

The device shown in the drawing is designed to bend a plurality of fiber tubes in a single operation. The bending device consists of a bed member 10 which carries the lower halves 11 of a plurality of tube forms. These forms are suitably bent in accordance with the desired conformation of the finished tubes. Coacting with the forms on the bed member is an upper member 12 carrying up per forms 13 complementary to the forms 11 carried by the bed member. The upper member 12 is provided with a plurality of grooved lugs 14 which'coact with posts 15 extending upwardly from the bed member, and the coaction of the lugs and posts insures the accurate positioning of the complementary halves of the tube forming members one upon the other. Spring catches 16 pivoted at 16 to the bed member are provided for holding the upper and lower members 10 and 12 together' after the bending operation is completed and while the fiber tubes herein designated as 17 are drying and hardening.

In operation of the device, the portions of the fiber tubes to be bent are soaked in water until the tubes become moist and flexible. This soaking operation is not essential where the bending operation takes place immediately after the tubes are formed from the pulp and before they have had an opportunity to set or harden. The moist flexible tubes are filled with sand or other granular material indicated at 18 in Fig. 4, the purpose of the granular material'being to main-- tain the circularity of the tubes during the bending operation and to prevent their collapsing. The granular material may be inserted either before or after the soaking operation.

The flexible tubes filled. with granular material are then placed in the tube bending forms and closed at their lower ends by means of gaskets 19, over which caps are placed. The caps rest against a foot plate2l extending upwardly and preferably formed integral with the bed member 10, which forms a rest or stop for the lower ends of the tubes. Extension shields or spades 22 conforming T7 in shape to that of the. tubes to be bent, are

pivoted as at 23 to the base member, and a bar 24 carried by rods 25 attached to two of the pivoted shields 22 is employed to prevent spilling of" the sand from the tubes.- Preferably an inner gas tight flexible plate 24: which may be of rubber, is secured to the bar 24, the purpose of which is to secure a closure for the tubes which is preferably gas tight. The function of the shields 22 is to prevent marring the outer surface of the tubes during the bending operation. After the tubes are in place and the members 19,. 20, 24 and 24 suitably fitted, the upper member 12 carrying the upper forms is lowered to the position shown in Fig. 4', thus bending the tubes. In this position the upper and lower members are clamped by means of the spring catches 16. The tubes after being bent are held in the forms until the moisture has dried and the tubes have set and hardened in the bent form. The drying operation may be hastened by applying heat, for example by placing the forms within an oven. lVhere heat is employed and expansion of the gas within the tubes takes place, the pres sure of the gas assiststhe. sand or granular material in maintaining the circularity of the tubes and if any irregularity has been produced due to the fact that the tubes were not completely filled with sand or granular material, the expanding gases completely fill the tubes and do away with suchirregularities.

The sand or granular material employed in the bending operation prevents any marring of the interior, and'produces uniformity of bending throughout. The granular material conforms itself to the flexible fibrous tube and insures complete circularity during the entire operation. It will be noted that the unbent portions of the tubes extend upwardly, as indicated in Fig. 4, and this has a tendency to cause the granular material to move toward the lower end of the tube, which is undergoing the bending operation. Thus, incase the filling of the tube is not complete, this is compensated for by the action of'gravity during bending.

While sand, is the material preferably used, owing to its cheapness and availability,

nevertheless other granular material may be used, as for example, sawdust. This mate-- rial may, if desired, be moistened, and under such circumstances the moisture. contained therein will expand into steam during the to the lowering of the upper member 12 and the clamping of the same in position, the purpose of such preliminary heating being to expand the gases within the tubes.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. A method. such as herein. described, which comprises inserting granular material into a. straight, moist, temporarily plastic fiber tube, bending the tube to the desired curvature while confining it against radial outwardv movement in any direction, and causing-said tube to set substantially rigidly while said granular material is inplace.

2. A method as herein described, which comprises moistening a straight fiber tube to render the same temporarily flexible and plastic, inserting granular material into the temporarily plastic tube, closing the ends of the tube gas tight, heating the tube to develop gas pressure, and bending to the desired curvature, then causing the tube to-set substantially rigidly while said granular material is in place.

3; A method of bending a moist fiber tube which comprises subjecting the tube tobending stress and simultaneously confining the outside of the tube to prevent radially outward movement in any direction and obstructing the inside against radially inward movement 1n any direction.

4:. A method of bending moist tubes which f comprises subjecting the tubes to bending stress while presenting resistance to radial movement in any direction either inward or outward.

In testimonywhereof I affix my signature.

DANIEL BENSON REPLOGLE'. 

